Ubuntu – Windows not booting in dual boot with Ubuntu 12.04 and Windows 7

Your partition layout looks odd, but then again this is how manufacturers do their OEM installations.

If this is a UEFI system, then reinstalling would be the quickest and straight forward way for getting a working installation. I recommend removing partitions sda5 through sda7, as they seem to be created by you. Then install Ubuntu from ubuntu-12.04-desktop-amd64.iso in UEFI mode (when selecting to boot from CD at boot time there should be two options for booting from CD one with UEFI and one without) to ensure that you're installing with UEFI support enabled. A partition layout with a Ubuntu partition and a separate home partition is a good choice. For using suspend to HDD (hibernate) you should choose at least the size of your RAM as the size of the swap partition. There is one additional step to be performed to re-enable hibernate in 12.04. After installation has finished you should have a Ubuntu with the grub-efi-amd64 package installed on your hard drive. The installer should have recognized the correct UEFI system partition (there is a specific GPT partition code for the UEFI system partition), put a grub-efi-stub in there and register it in the UEFI boot variables.

In the end you should have at least an entry each for Windows and Ubuntu in your UEFI boot up selection available. If you don't have a Windows related entry there, then this is probably not a UEFI system and you shouldn't attempt to try my suggested solution (you wouldn't be able to boot the CD in UEFI mode). Dual booting should be working via GRUBs chainloading mechanism, so setting Ubuntu via UEFI as the default boot option should work like dual booting worked in the past with GRUB.

For BIOS only:

If Boot-Repair will not see Windows and offer to install the syslinux boot loader, you can install it manually.

sudo apt-get install syslinux
sudo dd if=/usr/lib/syslinux/mbr.bin of=/dev/sda

You only want the syslinux boot loader as it is a Windows type boot loader that looks for more boot information in the partition with the boot flag. You do not want syslinux putting its additional boot data in the Windows partition, but want syslinux just to boot & pass boot to Windows code in the partition boot sector.

How to restore the Ubuntu/XP/Vista/7/8/10 BIOS bootloader